A fatwa is any religious decision made by mufti (Islamic scholar who is an interpreter or expounder of Islamic law).
The most infamous fatwa is the one by Ruhollah Khomeini sentencing Salman Rushdie (Muslim essayist) to death - that's why most Western people see fatwa just as a death sentence, although it's more than that.

2. n. Is the ultimate punishment given to any blasphemer who intentionally or unintentionally disrespects the mouslim religion, its leading teachers,imans, moulahs, ayatolahs, or its faithful. A bounty or death sentance.